Skin is the best cover for a raw surface caused by, for example, trauma or burns. The recipient area for the graft should have healthy granulation tissue with no evidence of infection.
Skin grafting is a surgical procedure that involves removing skin from one area of the body and moving it, or transplanting it, to a different area of the body. This surgery may be done if a part of your body has lost its protective covering of skin due to burns, injury, or illness.
Skin grafts are performed in a hospital. Most skin grafts are done using general anesthesia, which means you’ll be asleep throughout the procedure and won’t feel any pain.
Grafts can be classified by their thickness, the source, and the purpose. By source:
- Autologous: The donor skin is taken from a different site on the same individual’s body (also known as an autograft).
- Isogeneic: The donor and recipient individuals are genetically identical (e.g., monozygotic twins, animals of a single inbred strain; isograft or syngraft).
- Allogeneic: The donor and recipient are of the same species (human→human, dog→dog; allograft).
- Xenogeneic: The donor and recipient are of different species (e.g., bovine cartilage; pig skin; xenograft or heterograft).
- Prosthetic: Lost tissue is replaced with synthetic materials such as metal, plastic, or ceramic (prosthetic implants).
A split-thickness skin graft (STSG) is a skin graft including the epidermis and part of the dermis. Its thickness depends on the donor site and the needs of the person receiving the graft. It can be processed through a skin mesher which makes apertures onto the graft, allowing it to expand up to nine times its size. Split-thickness grafts are frequently used as they can cover large areas and the rate of autorejection is low. The same site can be harvested again after six weeks. The donor site heals by re-epithelialisation from the dermis and surrounding skin and requires dressings.
A full-thickness skin graft consists of the epidermis and the entire thickness of the dermis. The donor site is either sutured closed directly or covered by a split-thickness skin graft.
A composite graft is a small graft containing skin and underlying cartilage or other tissue. Donor sites include, for example, ear skin and cartilage to reconstruct nasal alar rim defects.
The patient should be given a general anaesthetic. The most commonly used donor site is the anterolateral or posterolateral surface of the thigh. First clean the selected donor site with antiseptic and isolate it with drapes. Apply petrolatum or liquid paraffin (mineral oil) to lubricate the area. Hold the assembled skin-grafting knife (Humby) in one hand and press the grafting board against the patient’s thigh ( or alternative donor site) with the other hand. Instruct an assistant to apply counter-traction to keep the skin taut by holding a second board in the same manner. Cut the skin with regular back-and-forth movements while progressively withdrawing the first board ahead of the knife.
After cutting a length of about 2 cm of skin, inspect the donor area: homogeneous bleeding confirms that the graft is of split-skin thickness; exposed fat indicates that the graft is of full thickness, i.e., too deep, in which case you should check the adjustment of the blade. As the cut skin appears over the blade, instruct an assistant to hold it gently out of the way with non-toothed dissecting forceps. Place the newly cut skin in saline and cover the donor area with a warm wet pack before dressing it with petrolatum gauze. Spread out the cut skin, with the raw surface upwards, on petrolatum gauze.
If a skin-grafting knife is not available, the graft can be taken with a razor blade held with straight artery forceps. Start by applying the cutting edge of the blade at an angle to the skin but after the first incision lay the blade flat.
Before applying the skin graft, clean the recipient area with saline. Wet the graft frequently with saline to prevent it from drying out. Do not pinch it with instruments. To graft a large piece of skin, first suture it in place at a few points and then continue to place sutures around the edges of the wound. Sutures are not necessary for a small piece of skin.
Haematoma formation under the graft is the most common reason for graft failure. It can be prevented by applying a “bolster” dressing made of moist cotton wool moulded in the shape of the graft and tied over the graft with sutures. As an alternative, make several small perforations in the graft, or cut the graft into small pieces (postage-stamp grafts) and place them a few millimetres from each other to leave space for bridging during the re-epithelization process.
Hold the graft in place with petrolatum gauze, unless you have already sutured it and applied a bolster dressing. Then apply additional layers of gauze and cotton wool, and finally a firm, even bandage. Leave the graft undisturbed for 2-3 days unless infection or haematoma is suspected. Change the dressing daily br every other day thereafter (a bolster dressing will no longer be needed by this stage), but never leave the grafted area uninspected for more than 48 hours. If the graft is raised, puncture it to release any serum underneath. Otherwise interfere as little as possible. It may be possible to expose the graft to the air at this early stage if the area can be protected by splints or mosquito netting, but only if there is adequate nursing supervision. After 7 to 10 days, remove any sutures, wash the grafted area, and lubricate it with liquid paraffin (mineral oil) or petrolatum.
The second week after grafting, instruct the patient in regular massage and exercise of the grafted area, especially if it is located on the hand, the neck, or one of the limbs. These exercises should be continued for at least 9 months. To prevent bum contractures, apply simple splints for flexure surfaces and keep the grafts under tension using whatever means is available. For example, simple tongue depressors can serve as finger splints and plaster of Paris can be used for extremities.